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I have been corrected several times recently for putting a comma before a conjunction in a sentence (splitting phrases, not items in a list). To each their own style guide, but my understanding was that (using 'and' as an example):

  • in the prehistoric era, the rule was to always put a comma before 'and', no matter the context
  • in the modern era, there are two schools of style about 'and', commas and the final item in a list (which I am not concerned with here)
  • in the modern era, you may put a comma before 'and' in a non-list to emphasise, indicate a pause, tweak meaning, etc. So that:

We will fight them on the beaches and the landing grounds.

has a slightly different meaning to

We will fight them on the beaches, and the landing grounds.

...but both are valid.

Is this comma in fact optional, or always to be discarded? Have I half-learned a (possibly out-moded) style rule without realizing it?

marked as duplicate by MrHen, Hellion, anongoodnurse, phenry, Matt E. Эллен Jan 22 '14 at 12:19

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  • hmm, perhaps english.stackexchange.com/questions/35171/… is a more suitable duplicate (it certainly answers the spirit of my question) – david.libremone Jan 21 '14 at 9:48
  • It is bad style, according to some or most style manuals. It is a good practice, according to experienced writers who can see where it is warranted and where superfluous, as also where it could potentially be an irritant. Good judgement determines if the comma is warranted in conveying the meaning clearly and unambiguously. ExSum: It's not always incorrect; it's certainly not 'optional', in the sense of leaving it to the writer's discretion. – Kris Jan 21 '14 at 10:49
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    By the way the sentence above is semantically bad. ... we shall fight on the beaches, we shall fight on the landing grounds ... --> ... we shall fight on the beaches, and on the landing grounds ... cf. we shall fight in the fields and in the streets, – Kris Jan 21 '14 at 10:55
  • I think it's OK if you're deliberately indicating that the 'and ...' is something of an after-thought tagged on. However in your example where beaches and landing grounds have equal status it's incorrect. I think I'd use ... anyway if I wanted to emphasise this, particularly in reported speech. For example, a speaker proclaiming "Freedom for all men ... and women." [after noticing women are present] – user24964 Jan 21 '14 at 11:14

The purpose of punctuation is to help the reader understand the grammatical structure of a sentence. In your example, the beaches and the landing grounds are equal complements of the preposition on. A comma after beaches would suggest that they were somehow not equal, and there is no reason to suppose that that is the case.

  • What if my purpose is to indicate that they are somehow not equal (may have to rethink my example to make this a possibility without it being too forced)? Is it bad / not worth doing with punctuation and better to write it out somehow? I can see why this would not apply to technical writing (my current specific context) - seems too unobvious and below the radar. – david.libremone Jan 21 '14 at 9:48
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    Do whatever you think makes the structure of the sentence clear to the reader. Put yourself in the position of the reader, and consider not so much what may or may not be bad or correct, but what makes the sentence easier to understand. In your example, you could change the emphasis by writing, for example, We will not only fight them on the beaches, but we will fight them on the landing grounds as well. – Barrie England Jan 21 '14 at 10:05

I'd omit the comma, as it sets up a false expectation of a second independent clause:

We will fight them on the beaches, and the landing grounds will be strewn with their dead bodies.

For contrast, if desired (though I'd have thought that 'beaches' and 'landing grounds' overlap confusingly here) I'd write:

We will fight them on the beaches – and in the fields and hills.

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